Ultrasonic velocities and ultrasonic densities of 3 (2'- aminophenyl)- 4-pyridoyl - 5 (2- hydroxyl phenyl) pyrazoles, in 70% acetone-water have been evaluated at 308.15 K by using interferometer at a frequency of 2.0 MHz. The ultrasonic velocity, density and concentration were used to calculate, partial molal volume (^v) apparent molar compressibility, intermolecular free length (Lf), Adiabatic compressibility (fis) Specific acoustic impedance (Z) and Relative association (R_A) to throw the light on the solute-solute interaction and solute-solvent interaction.